where K and Kb are equilibrium constants of adsorption in the presence of the nano-adsorbent and the corresponding bulk material, respectively.
From equation (22), it can be seen that the equilibrium constant of nanoadsorption is dependent on the bulk and interfacial components. Because r1P is smaller than rN, the equilibrium constant of nanoadsorption sharply increases when diameter of nano-adsorbent decreases. This is the reason that the nano-adsorbent elicits a strong adsorptive property. In addition, it can be seen that there is a positive relation between the equilibrium constant and the reciprocal of the diameter of the nano-adsorbent